Trap-doob



'STATES PATENT FFIQE.

GUSTAVUS RUNGE, OF PHILADELPHIA, PENNSYLVANIA..

TRAP-DOOR.

Specification of Letters Patent NEO. 11,254,l dated July 11, 1854.

To aZZ whom t may concern: f

Be it known that I, Gnsravns RUNGE, architect, ofthe city and county of Philadelphia, in the State of Pennsylvania, have invented a new and useful Improvement in Trap-Doors; and I do hereby declare that the following is a full and exact description thereof.

The nature of my invention consists in attaching counterbalances to a folding trapdoor, which is kept shut by a latch, after opening of which the counterbalances will raise the door folds and keep them in a rm perpendicular position until they are pulled down again by means of a cord and locked by the latch above mentioned.

To enable others skilled in the art to make and use my invention, I have furnished and will proceed to explain the following drawings Figure A, vertical section of four improved foldinff trapdoors in a second, third, fourth and ft-h story of a store, showing their construction and the arrangement of cords to workthem from below; Fig. B, transverse section of a trapdoor when shut; Fig. C, transverse section of a trapdoor when opened; Fig. D, plan of the same; Fig. E, plan of a trapdoor when shut; Fig. F, view of the peculiar framing of joists, seen from below, together with an under view of trapdoor; Fig. G, perspective view of one of the cast iron counterbalances, with the hinge journals attached to it, seen from above; Fig. I-I, front View and plan and section'of a small pillow block to support the pin attached to the hinge journals ci, Fig. G and Fig. I; Fig. I, side elevation on an enlarged scale of one of the counterbalances with hinge and pin (cZ) drawn in the perpendicular position attached to the tray door fold (a) Fig. K, front view and section of the latch k (Figs. A, B, C, D, E) tobe opened from below.

The alphabetical arrangement of the let ters is common to all the figures of the drawing.

The folding trapdoors ((L, a, a", am and b Z2 b" 5, Figs. A, B, G, D, E, and F,) are constructed in such a manner as to have no hinges or any other obstruc tions on the top of them making one smooth surface with the flooring above. The fold (a) catches over the fold (Z2) in the usual manner. The cast-iron counterbalances (0 c are fastened underneath to both folds by screws and nuts, the heads of the screws being let into the wood, so as to make no obstructions when the door is shut. The rod iron pins (CZ cl" Aare su ported by small pillow blocks (6 e .1), screwed to the side framing of the openings of hatchway.

In opening the t-rapdoor, the counter balances swing around below in the space between flooring and ceiling. The boards h 71. and f f" form a casing around this space, in which the counterbalances are working so that they are entirely hidden from view. To prevent the warping of the upper edges of boards f f small iron bars g g are screwed to them as shown in Figs C', D and I.

The counter balance 0 0 are hollow, and small rod iron pins (cl d d Figs. F, G, and I) are cast into the hollow spaces, for the purpose of fastening a quantity of sheet lead into them7 and in this manner to regulate the weight of the t-rapdoors.

My calculation of the weights of the different parts of construction for one size of hatchways is as follows: Weight of a yellow pine trapdoor fold, 5 feet by 2 feet 6 inches. with ledges, as shown in drawings, the whole being made out of one inch board, would be about pounds, the point of gravity being 16.5 inches from the axis (or center of pin d l). This arrangement would allow a counterbalan'ce of 990 pounds to one inch leverage. The difference of weights of the cast iron xtures (including hinges and screws) in favor ofthe opposite side of the aXis leaves 1175 pounds, with a leverage of 5.9 inches, or 693.25 pounds to one inch leverage. According to this calculation about 35 pounds of lead will be required in the place provided for it to overbalance the door fold. The hollow spaces in the counterbalanees c o are however large -enough to hold more than pounds of lead in each of them. The door folds, which in this manner would be raised by the counterbalances, are kept shut by a latch of very simple construction (7a 7.a Figs. A, B, C, D and This latch can be opened from below by pulling a cord (n, n, am, um', Fig. A) attached to the wire, which goes through the joist, (shown .in Fig. K by fw,) and also from above by treading or pressing on the lever (m, m,.m, mm', Fig. A) connected by a wire with another lever below, (Z, Z, Z", Z, Fig. A,) which changes the upward movement into the downward one, thus pulling also the wire attached to the lock (w, Fig. K) and opening the same. When the lock is opened, the counterbalances (c, c will immediately cause the doors to open and swing around until the upper faces of them strike the edges of flooring, (see Fig. A, second and third stories, and F ig. 1,) which keep the doors in a vlirm perpendicular position, the points of gravity being beyond the supported points and the weight of the door folds thus pressing against the edges of tlooring. To shut the door again, two cords are attached to the ends of the door folds near the wall, which run over two pulleys p, p 20, 20 and unite into me 00rd (QQ QG, Q Jelow a small weight (1, 1*, 1' 7W, Fig. A) attached to the end of it, to keep it ;tretched and prevent it from becoming eni-angled. All these small weights attached :o the cords for shutting the trap doors of phe different stories are cased in in the irst Fig. A,) having" story of store, to run up and down in the. casings whenever the dii'erent trap doors open or close. All the cords to ope the latches of the trap doors of all the different stories are also led down to the iirst story, from which eachtrap door of the hatchway may be opened and shut with ease.

What I claim as my invention and desire to secure by Letters Patent is- The application to trap doors of hatchways of counterbalance hidden from View and working between the flooring and ceiling substantially as specied, and the attachment of the hinges to the under side of the trap door to avoid all obstructions o-n the top of the same and making one smooth surface with the flooring above, as shown and described.

Philadelphia, November 21st, 1851.

GUSTAVUS RUNGE.

Witnesses:

S. BONNAPPON, G. HENRY MERKL. 

